1. Technical Field
The present invention relates to a mirror unit and an image capturing apparatus.
2. Related Art
A known mirror unit for a single lens reflex camera includes a main mirror, which is a half mirror, and a sub-mirror that reflects the light passed by the main mirror downward to a distance measuring sensor, and these mirrors are lowered into the optical path or raised above the optical path, as shown in Japanese Patent Application Publications No. 62-78536 and No. 63-95430. In such a mirror unit, a sub-frame holding the sub-mirror hangs down to be rotatable relative to a main frame holding the main mirror.
To achieve accurate distance measurement, it is desirable that measurement be started after vibration of the lowered sub-mirror has stopped. However, in this mirror unit, the vibration of the sub-mirror does not stop until the vibration of the lowered main frame has stopped. In other words, initiation of distance measurement is delayed because of the vibration of the main frame.